The present invention relates generally to disc drive data storage systems. More particularly, the present invention relates to configuring a disc drive to its most suitable capacity.
A typical disc drive data storage system can include multiple magnetic discs mounted for rotation on a hub or spindle. A spindle motor causes the discs to spin and the surface of the discs to pass under respective head gimbal assemblies (HGAs). The HGAs carry transducers which write information to, and read information from the disc surfaces. An actuator mechanism moves the HGAs from track to track across surfaces of the discs under control of electronic circuitry. Read and write operations are performed through a transducer which is carried on a slider body. The slider and transducer are sometimes collectively referred to as a head, and typically a single head is associated with each disc surface. The heads are selectively moved under the control of electronic circuitry to any one of multiple circular, concentric data tracks on the corresponding disc surface by an actuator device. Each slider body includes an air bearing surface (ABS). As the disc rotates the disc drags air beneath the ABS, which develops a lifting force which causes the head to lift and fly several microinches above the disc surface.
The current typical production process of disc drives utilizes a fixed sequence of tests to determine if a disc drive is capable of meeting the specification set for a capacity. If it does, then it is considered a passed drive. If it does not, then it is deemed a failed drive and the drive is diagnosed to determine the probable cause of failure and the rework needed. This process is relatively inefficient. The task of reworking is very time consuming and costly. It will physically involve operators doing the job. Often, rework yields are poor, primarily because there is no fixed rule as to a cause of a failure. The physical rework also means that a certain amount of production floor area and resources have to be used and allocated for the process. Thus, there is a need to include in the production process a way to predict the capacity the drive is able to take and hence configure it to that capacity.
The present invention provides a solution to this and other problems and offers other advantages over the prior art.
The present invention relates to configuring a disc drive to its most suitable capacity.
One embodiment of the present invention is directed to a method of configuring a disc drive. A data transfer capability of the disc drive is determined and the disc drive is configured based on the data transfer capability.
In one embodiment of the present invention, configuring the disc drive involves adjusting the data storage capacity of the disc drive based on the data transfer capability of the disc drive.
In another embodiment, the data transfer capability is determined for a plurality of head/disc surface combinations in the disc drive and the disc drive is configured based on the data transfer capabilities of each head/disc surface combination.
In a further embodiment, if the data transfer capability of the disc drive is below a first threshold, the bit density of the disc surface of an inferior head/disc surface combination is reduced and the bit density of the disc surface of a better head/disc surface combination is increased. If, after that, the data transfer capability of the disc drive remains below the first threshold, it is determined how many, if any, of the head/disc surface combinations have a data transfer capability below a second threshold. If one of the head/disc surface combinations have a data transfer capability below the second threshold, the head of said head/disc surface combination is disabled. If two or more of the head/disc surface combinations have a data transfer capability below the second threshold, the bit density of the entire disc drive is reduced.
Another embodiment of the present invention is directed to a program storage device that is readable by a computer system and that tangibly embodies a program of instructions executable by the computer system to perform a method of configuring a disc drive. Pursuant to the method, a write/read error rate is measured for each head/disc surface combination as a function of the bit density of the respective disc surfaces. Then a suitable drive configuration scheme is selected based on the error rate data. Next the selected drive configuration scheme is implemented.
In one embodiment of the program storage device, selecting a suitable drive configuration scheme involves selecting the scheme from multiple drive configuration schemes. In one of the drive configuration schemes, the bit density of the disc surface of one head/disc surface combination is reduced and the bit density of the disc surface of another head/disc surface combination is increased. Another of the drive configuration schemes involves disabling the head of a particular head/disc surface combination. A third drive configuration scheme involves reducing the bit density of the entire disc drive.